JPH05340439A - Rotary damper - Google Patents

Abstract

PURPOSE:To provide a rotary damper that is able to enlarge its damping force, after sealing a viscous fluid and a grain material in the filling part of a housing, as keeping the miniaturization by means of entwinement in both of them, as well as to prevent any unevenness in the damping force. CONSTITUTION:In a rotary damper composed of a housing 1 formed with a filling part 1b inside, a cap covering an opening of this housing, and a rotor shaft 2 being housed rotatably in the filling part of this housing and projected out of the cap, it is filled up with a grain material and a viscous fluid in the filling part, and moreover formed with plural pieces of blades 2b, jutting out in the radial direction at an equispace, in the rotor shaft being housed in the filling part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for opening and closing a cover plate rotatably attached to an audio device such as a cassette tape recorder or a video tape recorder under a predetermined braking force in a quiet and gentle manner. Of rotary damper.

[0002]

2. Description of the Related Art In a conventional rotary damper, a viscous fluid is sealed in a filling portion in a housing, or a fluid is sealed in the filling portion instead of the viscous fluid, and a rotor shaft is enclosed in the viscous fluid or granules. In some cases, the rotor shaft is rotated, and the rotation of the rotor shaft is braked by its viscous resistance or frictional resistance.

In order to increase the braking force in the rotary damper containing the viscous fluid, the gap between the rotor shaft and the housing is reduced, or the volume of the filling portion is increased to increase the rotor shaft. A large one is used and a large amount of viscous fluid is filled.

On the other hand, in order to increase the braking force in the rotary damper enclosing the above-mentioned granules, use small granules for the filling part and increase the amount or the volume of the filling part. Is increased, a large rotor shaft is used, and a large amount of particles are filled.

[0005]

By the way, in the case of filling the viscous fluid described above, there is a limit in reducing the gap between the rotor shaft and the housing. Further, even in the case of filling the granular material, if the filling portion is fully filled with the granular material, the rotor shaft cannot rotate. On the other hand, if the particles are filled to the extent that a space is created, the braking force becomes uneven.

Therefore, after all, in order to increase the braking force, there is no choice but to rely on increasing the capacity of the filling portion and increasing the amount of viscous fluid or particles, resulting in a large rotary damper. However, there is a problem in that the demand for miniaturization cannot be met.

The present invention is intended to solve the above-mentioned problems, and encloses a viscous fluid and granules in a filling portion of a housing to increase the braking force while maintaining downsizing due to the entanglement of both, and to suppress the braking force. It is an object of the present invention to provide a rotary damper that can prevent the occurrence of uneven power.

[0008]

A rotary damper according to the present invention is rotatably housed in a housing having a filling portion formed therein, a cap covering an opening of the housing, and a filling portion of the housing. A rotary damper having a rotor shaft having a shaft portion projecting from the cap, wherein the filling portion is filled with particles and a viscous fluid. A plurality of blades projecting in a radial direction at equal intervals are formed on the rotor shaft housed in.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotary damper according to the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a housing in which a bearing 1a projects inward at a central portion thereof, and a surrounding portion thereof is a filling portion 1b, and 2 has a shaft hole 2a which is rotatably supported by the bearing 1a. The outer peripheral surface of the shaft hole 2a is shown in FIG.
The rotor shaft has a plurality of blades 2b (four blades in the embodiment) protruding in the radial direction at equal intervals as shown in FIG.

In the embodiment shown in FIG. 1, the rotor shaft 2 has a non-circular projection 2c formed on its upper surface.
In the embodiment shown in FIG. 3, a gear portion 2d is formed on the outer peripheral surface. Further, in FIG. 1, reference numeral 3 is a gear having a non-circular hole 3a formed therein to be fitted into the protrusion 2c of the rotor shaft 2.

Reference numeral 4 denotes a cap, which is shown in FIG.
In FIG. 3, it is fitted and fixed to the outer peripheral surface of the opening of the housing 1, and in FIG. 3, it is fitted and fixed to the inner peripheral surface of the housing 1. The cap 4 has a shaft hole 4a in which the gear portion 3b of the gear 3 is inserted in the embodiment of FIG. 1, and a shaft hole 4a in which the gear portion 2 of the rotor shaft 2 is inserted in the embodiment of FIG. 4a is formed.

In addition, 5 in FIG. 1 and 6 and 7 in FIG. 3 are sealing members such as an O-ring, respectively, and in FIG. 1, the opening of the housing 1 and the outer peripheral portion of the gear 3 are formed. Between,
Further, in FIG. 3, they are interposed between the bottom of the housing 1 and the opening of the cap 4, and between the bottom of the cap 4 and the disc portion 2e of the rotor shaft 2.

Reference numeral 8 denotes granules, which are filled in the filling portion 4b of the cap 4 in the embodiment of FIG. 1 and in the filling portion 1a of the housing 1 in the embodiment of FIG. Filled with a viscous fluid such as oil. The granules 8 are made of, for example, alumina, which has high wear resistance and is not easily broken, and the size thereof is about 0.5 mmφ. In addition, the mixing ratio of the granules 8 and the viscous fluid is, for example, 80 to 90% of the granules and the rest is the viscous fluid.

The rotary damper thus constructed is shown in FIG.
If the rotor shaft 2 is rotated by an external force at,
The blades 2b rotate while being damped by the particles 8 and the viscous fluid. Further, in this case, the viscous fluid has a velocity of 0 at the boundary between the filling portions 1b and 4b, the same velocity as that of the rotor shaft 2 at the blade 2b of the rotor shaft 2, and the blade 2b and the filling portion 1 at the same speed.
It rotates so as to be sheared between the wall surfaces forming b and 4b.

On the other hand, the granules 8 are first pushed by the blades 2b, and rotate at a slower speed than the blades 2b while pushing the granules 8 which are successively connected to each other and under the influence of the viscous fluid. Therefore, the moving speeds of the particles 8 and the viscous fluid are different, and when the particles 8 move in the viscous fluid, viscous resistance is generated and a braking force is generated.

[0016]

As described above, according to the present invention, a viscous fluid and granules are enclosed in the filling portion of the housing, and when the blades of the rotor shaft rotate, the granules are moved in the viscous fluid to generate viscous resistance. I tried to get the braking force by
Even if the filling portion has a small volume, a sufficiently large braking force can be obtained. Therefore, the rotary damper can be miniaturized, and the braking unevenness can be improved as compared with the case where the braking force is obtained only by the particles. This has the effect of being able to obtain a smooth braking force without

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a rotary damper of the present invention.

FIG. 2 is a sectional view taken along line AA of the above.

FIG. 3 is a vertical sectional view of another embodiment of the present invention.

[Explanation of symbols]

 1 Housing 1b Filling Part 2 Rotor Shaft 2b Blade 4 Cap 4b Filling Part 8 Granules

Claims (2)

[Claims] 1. A housing having a filling portion formed therein, a cap covering an opening of the housing, and a rotor shaft rotatably housed in the filling portion of the housing and having a shaft portion protruding from the cap. In the constituted rotary damper, a granular body and a viscous fluid were filled in the filling section. 2. The rotor shaft housed in the filling portion,
The rotary damper according to claim 1, wherein a plurality of blades are formed at equal intervals so as to project in a radial direction.